Preheat your oven to 400ºF and line two baking sheets with parchment paper or silicone baking mats.
Place the oats and flax seeds in your spice grinder (or small food processor) and whiz until powdered, about 60 seconds.
Add the oat-flax flour, starch, baking powder, baking soda, and salt to a medium bowl, and whisk to combine.
In a mixing bowl, beat the yogurt, ½ cup sugar, margarine, and vanilla with a hand mixer until thoroughly combined. Fold in the dry mixture until combined, but do not over-mix. Stir in the chocolate chips.
The dough should be a cross between muffin batter and cookie dough. If too soft for spooning, place it in the refrigerator for 15 to 30 minutes to thicken.
Scoop dough into 6 mounds on your prepared baking sheet, and using damp hands, shape into domes. They spread a little during baking so go ahead and make those mounds a little tall. Sprinkle tops with remaining ½ tablespoon sugar.
Bake (I like to do one baking sheet at a time) for 12 to 15 minutes, or until just starting to turn golden around the edges and no shininess is peeking through the top.